Textile sheet material and process for producing same



ne as. i.

p H 3,a44,s91' 1C Patented July 1 TEXTILE SHEET MATERIAL AND PROCESS FOR PRODUCING SAlVIE Aifred Lauchenauer and Martin Schwemmer, Horn, Thnrgau, Switzerland, assignors to Raduner & Co. A.-G., Horn, Thurgau, Switzerland No Drawing. Filed Sept. 8, 1958, Ser. No. 759,427 Claims priority, application Switzerland Sept. 16, 1957 17 Claims. (Cl. 117-7) This invention relates to foldable, highly water resistant, stiffened textile sheet material of veryhigh dimensional stability, which can be printed by means of lithographic printing methods, and to a process for the production thereof.

Dimensional stability, i.e. in the sense of stability against reversible changes in dimensions of sheet material caused by changing degrees of humidity, is of highest importance not only in the actual use of maps, drawings, and the like, but'also in lithographic multicolor printing itself, since even small dimensional changes caused physically by the printing inks or mechanically by the printing treatment prevent the print from being accurate. In use, maps and drawings should remain substantially unaflccted as to areas of drawings or lengths of lines under different degrees of humidity and under different temperatures. Sheet material useful for maps, drawings, paper money or documents of all kinds should further be extremely resistant to abrasion, to folding and other forms of mechanical wear. Sheet material should also be capable of being printed in the form of single sheets in contrast to printing methods almost exclusively used in the textile industry, where printing is,

performed not on sheets of relatively, low area but on;

the full length of the piecesas'woven onthe loom.-

Tlie influence of the Water take-up on dimensional stability has been known in the field of plastics, but it has not become manifest to any important degree in the textile field, since in the case of fabrics dimensional changes of the fibre material itself caused by changesof the relative humidity of the surrounding atmosphere are dwarfed or even reversed by structural. influences on.

fabric dimensions, i.e. by factors related to spinning,

twisting, fabric construction, tightness of the weave, and' For example, although cellulose swells if' Wetted, i.e. the dimensions of the material itself increase,

the like.

ing, shrinkage control, and so on,'is basically different from that mentioned above.

Dimensional stability in the first sense, i.e. as used on the chemical nature of the material. It depends only insignificantly on pretreatments performed on the material, as long as such pretreatments do not change the chemical nature of the material itself,'and not on the way the material is processed before it was subjected to the test. In the case of dimensional stability mean ing fastness to shrinking in a textile sense the. opposite is true. There dimensional changes are almost exclusively governed by structural factors as mentioned above, and only to a minor degree by intrinsic properties It1therefore is ,used for changes of dimensions;

I of the fibre material itself, which is manifest by the fact that his impossible to predetermine shrinkage properties of a fabric merely by selecting from a strictly chemical point of view the fibre material to be used, disregarding spinning, throwing and weaving factors.

Attempts have been made to produce printed matter from textile material'such as fabrics, which during'use is subjected to Weathering, humidity and strong mechani cal wear. This'applies to sheet material used for draw ings, maps, documents, paper money, and the like. Printings on ordinary textile material, however, due to theease of movement between individual fibres and between groups of fibres, never can provide'a dimensional stability sufficient for use as maps or drawing paper. This is particularly true when the textile material is in a wet state. On the other hand, mechanical properties of paper are much inferior to those of textiles of comparable weight. I

It has also been proposed to coat glass .fibre fabrics with resinous material such as alkyd resins in order to obtain drawing material of high dimensional-stability. Glass fibre fabrics have, however, some serious disadvantages. First, glass fibres have very'high rigidity and hence rather low folding endurance, which in the case of maps, paper money, documents or other printed matter subjected to frequent folding in actual use, is a serious drawback; secondly, the adhesion of coatings, in particular of coatings applied from aqueous solutions, dispersions or emulsions, to glass fibres is known to be poor. Only if the glass fibre fabric is actually embedded in suitable coating material, i.e. if the coating material forms a continuous film of considerable thickness, is adequate adhesion obtained, which, however, makes necessary the use of excessively high amounts of coating material, and therefore results in intolerably high costs.

It has now been found according to this invention that textile sheet material can be provided which can be' printed as paper, having dimensional stability much superior to that of high quality printing paper. In addition, the product ofthis invention is much more resistant to mechanical wear, such' an abrasion, tearing, folding, and so on, thanpaper,

Thus, according to this invention there is provided a,

process for producing textile sheet material having high dimensional stability and high resistance to mechanical" wear and capable of being printed' by lithographic methods comprising treating a textile sheet material formed predominantly of organic fibers having a water take-up of less than abont 1.5%, by weight, at 20 C;

and 65% relative humidity to remove impurities adhering 1 to the fibres, applying to the textile sheet material a coat-' ing composition comprising (1) a pre-condensate ofa thermosetting resin, (2) a cross-linking agent capable ofreacting with at least two hydroxyl groups, (3) a poly-*- meric compound capable of being rendered substantially water-insoluble by reaction with said cross-linking agent,

i for plastic material or paper, is predominently governed by intrinsic properties of the material and hence depends and (4)'a catalyst capable of catalyzing the curing of the? thermosetting resin pie-condensate and the cross-linking action of the cross-linking agent, and heating thetextile;

material to cure the thermosettingresin pre-condensate" I and to effect cross-linking by means of the cross-linking agent, the textile material being subjected to tensioninc both a longitudinal and transverse directionduring the 1.5%, by weight, at C. and 65% relative humidity, the surface of said fibres having been freed from substantially all adhering impurities, having a coating resulting from subjecting to resin curing conditions a composition comprising (1) a pre-condensate of a thermosetting resin, (2) a cross-linking agent capable of reacting with at least two hydroxyl groups, (3) a polymeric compound capable of being rendered substantially water-insoluble by reaction with said cross-linking agent, and (4) a catalyst capable of catalyzing the curing of said thermosetting resin precondensate and the cross-linking action of said cross-linking agent.

It has been found that sheet material consisting of organic fibres with low water take-up such as 1.5% and preferably 0.5% or less gives much higher dimensional stabilization than those produced of fibres which take up a greater quantity of water such as 4% or more of water. A fabric woven from hexamethylenediamineadipate, water take-up of 4.5%, after being treated according to the present specification gave for instance in warp and weft directions a dimensional change more than ten times higher than that of an identically treated fabric made of poly-ethylene-terephthalate, water take-up of only 0.4%, when both fabrics were first conditioned in 60%, then in 80%, relative humidity. The dimensional stability to changes of humidity occurring in actual use of sheet material obtained by the process according to the present invention is as high as that of metal sheet material to temperature changes occurring in actual use.

Textile sheet materials suitable for the treatment according to the present invention are fabrics such as those woven from single yarns, or twisted yarns spun from filaments or cut staple fibres, or sheet material produced by bonding fibres together by means of polymeric material such as polymers of acrylic compounds, these fibres being either randomly distributed or oriented. The latter type sheet material is usually referred to as unwoven fabric and will be thus termed throughout the present specification. This sheet material, i.e. woven and unwoven fabrics, consist wholly or predominantly, e.g. about 75% or more, by weight, of organic fibres having at 20 C. and 65% relative humidity a water take-up of less than about 1.5%, preferably not more than 0.5%.

Typical of the materials from which the fibres may be made, as for example by spinning, are polymeric esters of a polyhydric alcohol, for example a dihydric alcohol such as a glycol, and a polybasic acid such as terephthalic acid. Polyethylene terephthalate is a preferred fibre material having a water take-up of only about 0.4% at 20 C. and 65% relative humidity.

Other fibre materials include acrylic polymers, such as polyacrylonitrile, and vinyl polymers such as polyvinyl chloride, polyvinyl alcohol, polyvinylidene chloride, polyethylene, polyisopropylene, and the like. Copolymers of acrylic compounds and vinyl compounds are also suitable for forming fibres of the sheet material, among which may be mentioned copolymers of acrylonitrile with vinyl chloride, and vinyl acetate, and polyvinylidene chloridepolyvinyl chloride Copolymers.

Other polymeric materials suitable for forming the fibres of sheet material according to this invention are modified cellulose, for example cellulose modified with acid such as cellulose triacetate, polyamides having at leastten methylene groups in the main polymer chain between reoccurring carbamide groups, such as polymeric omegaarnino-undecylic acid and polyurethane; polyamides produced from glycols having at least four methylene groups between hydroxy groups, and diisocyanates having at least six methylene groups between isocyanate groups.

Organic fibres such as mentioned above are much less rigid than glass fibres and have much higher folding endurance. They provide much higher adhesion to waterborne improving agents, and adhesion of coatings such as these described hereinafter is very good, even if the coating does not form a continuous film, i.e. with low or only moderate amounts of coating agents.

It has been found that best results are obtained by removing impurities adhering to the fibres as completely as possible before applying the-coating composition. This not only results in better adherence of the coating composition to the fibres, but surprisingly makes the coating more elficient, i.e. a given amount of improving agent gives much more stiffness on a thoroughly precleaned fabric than on a grey fabric or on an incompletely cleaned fabric. Similarly, the precleaned fabric gives better folds when folded as in the case of maps. The increase of the stiffness obtained on precleaned textile material is important since it not only enables the saving of considerable quantities of coating compositions, but since the percentage of composition applied, based on the weight of the textile material, cannot be increased indefinitely, on one hand because the sheet material becomes too thick and bulky for the subsequent printing operation, on the other band due to the fact that coatings of excessive thickness tend to become brittle and to dust off on creasing.

Impurities which are removed by the cleaning step are: sizes, spinning oils, softeners, antistatic agents, wetting agents, humidifying agents, insufiiciently polymerized fibre material, secondary reaction products formed in polymerisation, in spinning or in processing of the fibre material, or extraneous matter or soil of any kind which adheres to the textile sheets.

Such impurities usually are only incompletely removed by scouring treatments which in textile finishing usually precede dyeing or bleaching. Thus, in order to get complete removal one may either apply usual scouring methods under more severe conditions, such as at higher temperatures, for prolonged periods and/ or with higher concentrations of washing agents than usual, dropping the bath repeatedly to avoid redeposition of the impurities removed from the fibres, or one may increase the scouring action by mechanical means such as strong agitation of the bath and/or the textile material, or physically by the action of sonic or ultransonic waves.

Fibres particularly free of impurities are obtained by subjecting the textile sheet material to the action of agents capable of dissolving, degrading or very strongly swelling the fibre material under conditions as to concentration of the agent, temperature and duration of the treatment, which cause only superficial changes of the fibres without substantial loss of fibre strength. Impurities are thus removed very efficiently and rapidly without seriously affecting the mechanical properties of the fibre material and without making fibres stick together. Adherence of the composite improving agent applied subsequently to textiles thus pretreated is excellent due to the slight eroding action of the treatment. .Examples of such treatments are: treatment of polyester fibres with aqueous solutions of alkali hydroxides, treatment of polyamide fibres with acids or acidic compounds, treatment of acrylic fibres with compounds capable of dissolving such fibres. These compounds may be applied in the form of solutions and emulsions, or in vapor. phase. The application of solvents of course is not limited to acrylic fibres, but may be extended to all fibres suitable for the process according to the present specification. Other treatments include superficially saponifying triacetate fibres or other fibres with saponifiable end groups with compounds of alkaline reaction, and strongly swelling polyester or acrylic fibres wtih phenolic compounds. All these agents should be subsequently removed from the textile material by thoroughly rinsing, neutralizing or other suitable means.

Such agents as mentioned above may be added to the securing bath, to bleaching liquors or any other wet treatment bath, or they may be applied in separate baths.

Nonionic, anionic or cationic surface active agents may be used in scouring and/or rinsing operations, and solutions or emulsions or dispersions of compounds having a solvent action on impurities may be used. These cleaning, i.e. a Superficial dissolution may for instance be effected either in an alkaline bleaching bath ortprior to or subsequently to bleaching or any other pretreating operation usually applied to synthetic textile material.

As stated above, the coating composition employed in the process of this invention comprises l) a pre-condensate of a thermosetting resin, (2) a cross-linking agent capable of reacting with at least tWo hydroxyl groups, (3) a polymeric compound capable of being rendered substantially water-insoluble by reaction with said crosslinking agent, and (4) a catalyst capable of catalyzing the curing of the thermosetting resin pre-condensate and cross-linking of the cross-linking agent.

Suitable heat-setting resins, used in form of soluble pre-condensates, are for instance reaction products of amides with aldehydes, for example reaction products of melamine, urea, substituted urea, dicyandiamide, and hydantoins with formaldehyde, glyoxal, and acrolein. Other thermosetting resin pre-condensates which may be employed are reaction products of aldehydes with ketones or with phenolic compounds; however these pre-condensates tend to discolor on storage or on exposure to light. Thus, the amide-aldehyde pre-condensates are preferred.

Cross-linking agents found suitable for insolubilizing polymeric compounds comprise formaldehyde, glyoxal, polyisocyanates, and polyepoxides, i.e. compounds capable of reaction with at least two hydroxy groups, and compounds capable of releasing such compounds in the presence of catalysts and/or on heating, e.g. compounds capable of releasing formaldehyde on heating in presence of acidic catalysts.

Polymeric compounds capable of being rendered insoluble by the action of the cross-linking agent and hence suitable for incorporation into the composite improving agent comprise starch or derivatives thereof, polyvinyl alcohol .or derivatives thereof, polyesters having hydroxy end groups, other polymeric bodies carrying a plurality of hydroxy groups or other functional groups capable of reacting with the cross-linking agent.

Ratios between pre-condensate of heat-setting resin, cross-linking agent and polymeric compound capable of being rendered insoluble vary depending on the particular ones selected, the structure andkind of the fibre material, and the textile goods used, and the effects desired. Generally speaking, the ratio between the combined dry weights of the resin pre-condensate plus the cross-linking agent and the polymeric compound mayvary from 1:2. to 2:1, 2:3 being a preferred ratio, while the ratio between resin pre-condensate and cross-linkin g agent may vary in wider range, i.e. from about 1:10 to aboutslozl. All the ratios given above apply to the dry weight of the materials.

Expressed in terms of weight percent, the pre-condensate may comprise from about 20 to about 34%, the cross-linking agent from about to about 45% and the polymeric compound capable of being rendered substantially water-insoluble by reaction with the cross-linkin agent from about 20 to about 60%. I

The composite improving agent or coating composition may be applied to the textile material thus pretreated by padding, spraying, printing or by any one of the known coating methods, either in one or several steps. It may be applied as an aqueous or non-aqueous solution, as an emulsion or as a dispersion. V

The cure of the resin pre-condensates andthe insolubilization of the polymeric compounds is affected by catalysts, usually at elevated temperatures. Particularly suitable as catalysts are acidic compounds, i.e. compounds showing acid reaction or-potential acid reaction. Such catalysts have been known for a long time. In cases where isocyanates are used as cross-linking agents adding nitrogeneous compounds as catalysts for the reaction of the isocyanate groups with hydroxy groups may prove advantageous.

In addition to the resin pre-condensate, the cross-linking agent, the polymeric compound and the catalyst, the

composite improving agent may also contain other known agents such as fillers, pigments, abrasives giving tooth to the surface, i.e. improving the'reception of the graphite markings from drawing pencils, softening agents, dyestuffs, hydrophobing agent, plastifying agents, silicones, fiameproofing agents, compounds sensitive to light-or to other sources of radiation.

The stretching step mentioned before may be effected in the pretreatment or in any subsequent phase, but prior to the curing step. It prevents unevenness of the end product, formation of creases and wrinkling. It is preferably effected in combination with drying, padding, coating, calendering, either in wet state or dry, either by stretching in both a longitudinal and transverse direction simultaneously or at different times.

To modify the surface to make it smooth or provide a pattern such as for instance fine parallel lines, or to give it tooth, the textile sheet material may be subjected to mechanical deformation, in particular to calendering, schreinering or embossing, in any phase after the precleaning step, but prior to the final curing step, prefer- I ably at elevated temperatures, which are, however, at least 20 C. below the softening point of the thermoplastic fibre material, i.e. at least 20 C. below the term perature where the thermoplastic properties of the material become manifest, in order to avoid fusing together of the yarns at their intersections, which would severely affect the tearing strength of the sheet material.

Not only mechanical deformation, but also any other treatment involving heat is, according to the present specification, to be effected under conditions as to temperature and/or pressure which prevent the fusing together of yarns at yarn intersections.

The sheet material treated according to the present invention may, after the curing step, be cut into sheets of any desirable dimensions and then printed, or it may be printed in full length prior to cutting. Also, the sheet material may be treated, in full length or after cutting, with known agents, such as agents sensitive to light or other kinds of radiation, with slightly abrasive agents to improve the reception of graphite markings from the drawing pencil, and the like.

The following are examples of this invention.

Example I A cretonne fabric made of denier filament yarn spun from polyethylene terephthalate, water take-up of 0.4% at 20 C. and 65% relative humidity, is scoured for one hour at C. in the presence of a nonionic detergent, the bath being dropped twice. It is then dried on a stenter frame to grey Width by exerting weftwise tension. The fabric is then coated by means of a doctor blade, which is mounted in front of a drum of in diameter heated to C. The fabric passes 'under' the knife coater and then around the drum, where it is dried. Warpwise tension is applied during the coating treatment. The coating composition used for coating consists of:

Grams per liter Trimethylolmelamine (thermosetting resin precondensate) 60 Formaldehyde (cross-linking agent) 60 Polyvinyl alcohol (polymeric compound) Ammonium sulfate (acidic catalyst) 20 Titanium dioxide (pigment) 50 The fabric thus treated is rather stiff and can be printed in the form of sheets on lithographic printing equipment V 7 used for printing of paper. Dimensional stability and resistance to mechanical wear are good. No appreciable deterioration takes place if the fabric is buried in soil for several weeks.

Example II The process of Example I is repeated with the exception that the pre-treatment (scouring) described in the previous example is intensified by the addition of caustic soda to the scouring bath.

Example III The process of Example I is repeated with the exception thatthe following coating composition is employed:

Parts by weight Dimethylol-ethylene urea (thermosetting resin precondensate) 3 Glyoxal (cross linking agent) 2 Starch (polymeric compound) 6 Triethanolamine hydrochloride (acidic catalyst). Diatomaceous earth (mild abrasive).

Example IV A fabric (toile) made of polyethylene terephthalate fibres (filament, 80 denier in warp, 60 denier in filling) is pre-cleaned by treating with aqueous solutions of sodium hydroxide at C. with caustic soda of to Baum strength until the fabric has lost 6 to 8% of its weight (the caustic soda reacting superficially with the polyester fibre and thus removing surface impurities very thoroughly). After neutralization and rinsing the fabric is coated as described in Example I with the coating composition described in said example. The sheet material thus obtained is much stiffer and the adhesion of the coating to the fabric much better than in the case of the same fabric washed with water instead of being pretreated with alkali. Dimensional stability is 2 to 3 times higher than that of high quality lithographic paper.

Example V A fabric (taffeta) made of fibre spun from polyacrylonitrile (Orlon 81 manufactured by Du Pont) is thoroughly pre-cleaned by superficially modifying the fibre chemically and eroding it at the surface by treatment for 10 seconds with the solution of 10%, by weight, of sodium hydroxide in ethylene glycol at 150 C., followed immediately by neutralization in dilute hydrochloric acid and rinsing until the fabric shows neutral reaction. The fabric is then bleached with sodium chloride in the presence of phosphoric acid, and dried under weftwise tension. Prior to applying the composite improving agent the fabric is calendered under 30 tons pressure at 140 C. in order to obtain a smooth surface.

The fabric is coated with the following composition:

Grams per liter Dimethylol urea (thermosetting resin pre-condensate) 60 Quaker Reactant SC, polymeric condensation product of formaldehyde and acetal (crosslinking agent) 90 Oxy-ethyl-starch (polymeric polyhydroxy compound) 150 Silicone hydrophobing agent 30 Magnesium chloride (acidic catalyst) 20 Organic pigment (blue) 3 Each side of the fabric is coated once under tension warpwise. The fabric is then heated to 140 C. for 5 minutes for curing.

Example VI A fabric (sateen) made of cellulose triacetate fibres is pre-cleaned by treating it with an aqueous emulsion of methyl isobutyl ketone. It is then dyed, thoroughly rinsed and dried. The following composite improving agent is applied by padding:

parts dimethylol ethylene urea (resin pre-condensate parts poxy resin, organic diepoxide compound as described in Epoxy Resins in the Crease Proofing of Cotton by C. W. Schroeder and F. E. Condo, Textile Research Journal, vol. XXVII, No. 2, February 1957, pp. 135-445 (Eponite mfd. by Shell Chemical Corp.)

30 parts polyvinyl alcohol (polymeric compound) 10 parts Zinc fluoborate (acidic catalyst) 500 parts (water) The fabric is dried under tension in warp and weft and then heat-treated at 160 C. for 3 minutes without tension.

Example VII An unwoven fabric sheet material consisting of Rilsan polyamide fibres, in which the polyamide has ten methylene groups in the main polymer chain between reoccurring carbamide groups and produced from omega amino-undecanoic acid (water take-up under normal conditions 1%) treated with Chemigum Latex, a copolymerisate of acrylonitrile and an acrylic acid ester (manufactured by Goodyear Chemical Corp.) is treated for 10 to 15 seconds with hydrochloric acid (13% strength) at 50 to 80 C. to obtain superficial degradation of the polyamide fibre and hence complete removal of impurities, and to make the fibre surface more receptive to the composite improving agent by slight surface erosion. The unwoven fabric is immediately afterwards neutralized and rinsed thoroughly. After drying it is sprayed with the composite improving agent described in Example I, dried and heat-treated to cure the resin.

Example VIII A fabric (toile) made of staple fibre material spun from a copolymerisate of acrylonitrile and vinylchloride (Dynel manufactured by Union Carbon & Carbide) is pie-cleaned by first scouring in the presence of an anionic detergent and an emulsifying agent and then bleaching with sodium chlorite. After rinsing the fabric is dried under light weftwise tension. It is then coated as described in Example I under warpwise tension, calendered at 50 C. and cured at C. for 12 minutes.

Example IX A fabric made of polyvinylidene chloride copolymerisate fibre (Saran manufactured by Dow Chemical Company) is pre-cleaned by scouring in a bath containing a nonionic detergent and emulsified perchlorethylene.

. After drying it is coated with the following composition:

Two coatings on the same side are applied. The fabric is dried after each coating and then heat-treated for 10 minutes at C. to obtain curing of the resin precondensate and fixation of the polymeric polyhydroxy compound.

Example X A fabric (taffeta) made of polyethylene fibres is precleaned and coated as described in Example 1.

Example XI A=Sheet material produced according to the present invention B=L1thograph1c paper as used for high-quality mapprinting Dimensional change per change of relative humidity in the range of 60 to 85% relative humidity:

longitudinal direction, percent 0.026 0. 08 transverse direction, percent 0.028 0.17 Dimensional change per 10% change of relative humidity in the range of 18 to 60% relative humidity:

longitudinal direction, percent 0.038 0. 060 transverse direction percent 0.034. 0.13 Residual dimensional change after conditioning cycle 60%80%18%60% relative humidity:

longitudinal direction, percent. 0.024 0. 105 transverse direction, percent.-- -0.014 0. 161 Folding endurance (Schopper):

longitudinal direction above 20,000. 900-l500 transverse direction above 20,000. 900-l500 Bursting strength:

dry 175 '55 wet--.- I 18*; 25 Tensile strength:

longitudinal direction, kg 12 transverse direction, kg. 6 Thickness, millimeters 7 0.102

As is seen from the above table the product as obtained according to the present invention is far superior to pa per. It also shows much more uniform dimensional sta bility, i.e. in the case of paper dimensional changes in longitudinal direction are distinctly difierent from those in transverse direction, while in the case of product A both directions give similar values.

The dimensional stability of product A in fact is in the same range with that of metal underchange's in atmospheric conditions as are likely to occur in. use. In the case of the product produced according to the invention such mechanical properties as tearing strength, tensile strength, and bursting strength can easily be predetermined, and can be varied at will in one or both'directions, simply by using textile fabrics of suitable construction and composition and thus adapted to the requirements of the intended end use of the product without unduly increasing weight and thickness, while in the case of paper this is hardly possible.

Fabrics may be heat-set after the precleaning step or in any phase afterward-s to get uniform appearance or resistance to creasing in subsequent wet treatments taking place prior to the application of the composite improving agent. hardly improves dimensional stability of the end product.

It will be understood that numerous changes and substitutions may be made of the materials and the method of their preparation and use without departing from the spirit of the invention especially as defined in the appended claims.

We claim:

1. A process for producing textile sheet material having high dimensional stability and high resistance to mechanical Wear and capable of being printed by lithographic methods comprising treating a textile sheet ma- It has, however, been found that heat-setting terial formed predominantly of organic fibers having a water take-up of less than about 1.5%, by weight, at 20 C. and 65% relative humidity toremove impurities adhering to said fibers, applying to said textile sheet material a coating composition consisting essentially'of (1) from about 20 to about 34%, by weight, of a pre-condensate of a thermosetting resin consisting of the reaction product of an amide with an aldehyde, (2) from about 10 to about 45%, by weight, of a cross-linking agent capable of reacting with at least two hydroxyl groups selected from the group consisting of aldehydes containing not more than three carbon atoms, polyisocyanates, and polyepoxides, (3) from about 20 to about 60%, by weight, of a polymeric compound capable of being rendered substantially water-insoluble by reaction with said cross-linking agent selected from the group consisting of starch, starch derivatives, polyesters having hydroxyl end groups, and vinyl compounds carrying a plurality of hydroxyl groups and (4) an acidic catalyst capable of catalyzing the curing of said thermosetting resin pre-condensate and;

the cross-linking action of said cross-linking agent, and heating said textile material to cure said thermosetting resin pre-condensate and to effect cross-linking of said polymeric compound by means of said cross-linking agent, said textile material being'subjected to tension in both a longitudinal and transverse direction during said process and prior to said heat treatment.

2. The process according to claim 1 in which said textile sheet material comprises at least 75%, by weight, of

organic fibres having a water take-up of less than about 0.5% at 20 C. and 65 relative humidity.

3. The process according to claim 1 in which said textile sheet material is subjected to'tension subsequent to 1 mechanical deformation being at leastabout 20 C. be-i low the softening range of the organic fibres comprising said textile material.

6. A process for producing textile sheet material having high dimensional stability and high resistance to mechanical wear. and capable of being printed by lithographic' methods comprising treating a textile sheet material formed predominantly of organic fibers having a water, take-up of less than about 1.5%, by weight, at 20 C. 1 and 65% relative humidity and comprising a material selected from the group consisting of polyesters of a polyhydric alcohol and a polybasicacid, acrylic polymers,

vinyl polymers, modified cellulose, and polyamides hav-.

ing at least ten methylene groups in the main polymer chain between reoccurring carbamide groups, toremove impurities adhering to said fibers, applying to said textile sheet material a coating composition consisting essentially of (1) from about 20 to about 34%, by weight, of a pro-condensate of a thermosetting resin consisting of... the reaction product of an amide with an aldehyde, (2) from about 10 to about 45%, by weight, of across-link ing agent capable of reacting with at least two hydroxyl groups selected from the group consisting of aldehydes containing not more than three carbon atoms, polyiso cyanates, and polyepoxides, (3) from about 20 to about 60%, by Weight, of a polymeric compound capable of being rendered substantially water-insoluble by reaction with said cross-linking agent selected from the group consisting of starch, starch derivatives, polyesters having hydroxyl end groups, and vinyl compounds carrying a plu rality of hydroxyl groups and (4) an acidic catalyst capable of catalyzing the curing of said thermosetting resin pre-condensate and the cross-linking action of said crosslinlting agent, and heating said textile material to cure said thermosetting resin pre-condensate and to effect crosslinking of said polymeric compound by means of said cross-linking agent, said textile material being subjected to tension in both a longitudinal and transverse direction during said process and prior to said heat treatment.

7. The process according to claim 6 in which said textile sheet material comprises at least 75%, by weight, of organic fibres having a water take-up of less than about 0.5% at 20 C. and 65 relative humidity.

8. The process according to claim 6 in which said textile sheet material is subjected to tension subsequent to said treatment for removing impurities adhering to said organic fibres.

9. The process according to claim 6 in which said textile sheet material consists substantially entirely of organic fibres having a water take-up of less than about 1.5% at 20 C. and 65% relative humidity.

10. The process according to claim 6 in which said textile sheet material is subjected to mechanical deformation subsequent to said treatment for removing impurities adhering to said organic fibres and prior to said heat treatment, the temperature of said sheet material during said mechanical deformation being at least about 20 C. below the softening range of the organic fibres comprising said textile material.

11. The process according to claim 6 in which said textile sheet material is printed by lithographic methods subsequent to said heat treatment.

12. A textile sheet material having high dimensional stability and high resistance to mechanical wear and capable of being printed by lithographic methods comprising sheet material formed substantially entirely of polyethylene terephthalate fibers having a water take-up of less than about 1.5%, by weight, at 20 C. and 65 relative humidity, said fibers being substantially free from adhering surface impurities, and having a coating consisting essentially of the acid catalyzed product of reaction between about 20%, by Weight, of trimethylolmelamine, about 20%, by weight, of formaldehyde, and about 60%, by weight, of polyvinyl alcohol.

13. Textile sheet material according to claim 12 having lithographic printing on a surface thereof.

14. A textile sheet material having high dimensional stability and high resistance to mechanical wear and capable of being printed by lithographic methods comprising sheet material formed substantially entirely of polyethylene terephthalate fibers having a water take-up of less than about 1.5%, by weight, at 20 C. and 65% relative humidity, said fibers being substantially free from adhering surface impurities and having a coating consisting essentially of the acid catalyzed product of reaction between about 3 parts, by weight, of dimethylolethylene urea, about 2 parts, by weight, of glyoxal, and about 6 parts, by weight, of starch.

l5. Textile sheet material according to claim 14 having lithographic printing on the surface thereof.

16. A textile sheet material having high dimensional stability and high resistance to mechanical wear and capable of being printed by lithographic methods comprising sheet material formed predominantly of organic fibers having a water take-up of less than about 1.5%,

by weight, at 20 C. and 65% relative humidity, said fibers being substantially free from adhering impurities, and having a coating consisting essentially of the acid catalyzed product of reaction between 1) from about 20 to about 34%, by weight, of a pre-condensate of a thermosetting resin consisting of the reaction product of an amide with an aldehyde, (2) from about 10 to about 45%, by weight, of a cross-linking agent capable of reacting with at least two hydroxyl groups selected from the group consisting of aldehydes containing not more than three carbon atoms, polyisooyanates and polyepoxides, and (3) from about 20 to about by weight, of a polymeric compound capable of being rendered substantially water-insoluble by reaction with said cross-linking agent selected from the group consisting of starch, starch derivatives, polyesters having hydroxyl end groups, and vinyl polymers carrying a plurality of hydroxyl groups.

17. A textile sheet material having high dimensional stability and high resistance to mechanical wear and capable of being printed by lithographic methods comprising sheet material formed predominantly of organic fibers having a water take-up of less than about 1.5%, by weight, at 20 C. and relative humidity and comprising a material selected from the group consisting of polyesters of a polyhydric alcohol and a polybasic acid, acrylic polymers, vinyl polymers, modified cellulose, and polyamides having at least ten methylene groups in the main polymer chain between reoccurring carbamide groups, said fibers being substantially free from adhering impurities, and having a coating consisting essentially of 1) from about 20 to about 34%, by weight, of a precondensate of a thermosetting resin consisting of the reaction product of an amide with an aldehyde, (2) from about 10 to about 45%, by weight, of a cross-linking agent capable of reacting with at least two hydroxyl groups selected from the group consisting of aldehydes containing not more than three carbon atoms, polyisocyanates, and polyepoxides, (3) from about 20 to about 60%, by weight, of a polymeric compound capable of being rendered substantially water-insoluble by reaction with said cross-linking agent selected from the group consisting of starch, starch derivatives, polyesters having hydroxyl end groups, and vinyl compounds carrying a plurality of hydroxyl groups.

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS Great Britain Nov. 27, 1945 OTHER REFERENCES Ser. No. 233,292, Schubert et al. (A.P.C.), published H May 4, 1943. 0 

1. A PROCESS FOR PRODUCING TEXTILE SHEET MATERIAL HAVING HIGH DIMENSIONAL STABILITY AND HIGH RESISTANCE TO MECHANICAL WEAR AND CAPABLE OF BEING PRINTED BY LITHOGRAPHIC METHODS COMPRISING TREATING A TEXTILE SHEET MATERIAL FORMED PREDOMINANTLY OF ORGANIC FIBERS HAVING A WATER TAKE-UP OF LESS THAN ABOUT 1.5%, BY WEIGHT, AT 20* C. AND 65% RELATIVE HUMIDITY TO REMOVE IMPURITIES ADHERING TO SAID FIBERS, APPLYING TO SAID TEXTILE SHEET MATERIAL A COATING COMPOSITION CONSISTING ESSENTIALLY OF (1) FROM ABOUT 20 TO ABOUT 34%, BY WEIGHT, OF A PRE-CONDENSATE OF A THERMOSETTING RESIN CONSISTING OF THE REACTION PRODUCT OF AN AMIDE WITH AN ALDEHYDE, (2) FROM ABOUT 10 TO ABOUT 45%, BY WEIGHT, OF A CROSS-LINKING AGENT CAPABLE OF REACTING WITH AT LEAST TWO HYDROXYL GROUPS SELECTED FROM THE GROUP CONSISTING OF ALDEHYDES CONTAINING NOT MORE THAN THREE CARBON ATOMS, POLYISOCYANATES, AND POLYEPOXIDES, (3) FROM ABOUT 20 TO ABOUT 60%, BY WEIGHT, OF A POLYMERIC COMPOUND CAPABLE OF BEING RENDERED SUBSTANTIALLY WATER-INSOLUBLE BY REACTION WITH SAID CROSS-LINK ING AGENT SELECTED FROM THE GROUP CONSISTING OF STARCH, STARCH DERIVATIVES, POLYESTERS HAVING HYDROXYL END GROUPS, AND VINYL COMPOUNDS CARRYING A PLURALITY OF HYDROXYL GROUPS AND (4) AN ACIDIC CATALYST CAPABLE OF CATALYZING THE CURING OF SAID THERMOSETTING RESIN PRE-CONDENSATE AND THE CROSS-LINKING ACTION OF SAID CROSS-LINKING AGENT, AND HEATING SAID TEXTILE MATERIAL TO CURE SAID THERMOSETTING RESIN PRE-CONDENSATED AND TO EFFECT CROSS-LINKING OF SAID POLYMERIC COMPOUND BY MEANS OF SAID CROSS-LINKING AGENT, SAID TEXTILE MATERIAL BEING SUBJECTED TO TENSION IN BOTH A LONGITUDINAL AND TRANSVERSE DIRECTION DURING SAID PROCESS AND PRIOR TO SAID HEAT TREATMENT. 